Clinical experience with daptomycin: bacteraemia and endocarditis

Calculated parenteral initial treatment of bacterial infections: Introduction and antibiotics

This is the first chapter of the guideline "Calculated initial parenteral treatment of bacterial infections in adults - update 2018" in the 2nd updated version. The German guideline by the Paul-Ehrlich-Gesellschaft für Chemotherapie e.V. (PEG) has been translated to address an international audience. This guideline is a revision of the recommendations published in 2010, taking into account recent substances and studies. As with previous revisions, the current situation of pathogen resistance and the results of new clinical trials are considered. The results are the present recommendations for parenteral calculated initial therapy of bacterial infections in adults. If several treatment options are mentioned, they are not always equivalent in their spectrum of microbiological activity. Therapeutic alternatives offer the opportunity to consider pathogen epidemiology, to avoid antibiotic intolerances or to escalate or de-escalate treatment in a manner suited to the situation. This article describes the different therapy options.

[S2k guidelines of the PEG on calculated parenteral initial treatment of bacterial diseases in adults : Focussed summary and supplementary information on antibiotic treatment of critically ill patients]

In January 2018 the recent revision of the S2k guidelines on calculated parenteral initial treatment of bacterial diseases in adults-update 2018 (Editor: Paul Ehrlich Society for Chemotherapy, PEG) was realized. It is a helpful tool for the complex infectious disease setting in an intensive care unit. The present summary of the guidelines focuses on the topics of anti-infective agents, including new substances, pharmacokinetics and pharmacodynamics as well as on microbiology, resistance development and recommendations for calculated drug therapy in septic patients. As in past revisions the recent resistance situation and results of new clinical studies are considered and anti-infective agents are summarized in a table.

Daptomycin Pharmacokinetics and Pharmacodynamics in Septic and Critically Ill Patients

Infections, including sepsis, are associated with high mortality rates in critically ill patients in the intensive care unit (ICU). Appropriate antibiotic selection and adequate dosing are important for improving patient outcomes. Daptomycin is bactericidal in bloodstream infections caused by Staphylococcus aureus and other Gram-positive pathogens cultured in ICU patients. The drug has concentration-dependent activity, and the area under the curve/minimum inhibitory concentration ratio is the pharmacokinetic/pharmacodynamic (PK/PD) index that best correlates with daptomycin activity, whereas toxicity correlates well with daptomycin plasma trough concentrations (or minimum concentration [C min]). Adequate daptomycin exposure can be difficult to achieve in ICU patients; multiple PK alterations can result in highly variable plasma concentrations, which are difficult to predict. For this reason, therapeutic drug monitoring could help clinicians optimize daptomycin dosing, thus improving efficacy while decreasing the likelihood of serious adverse events. This paper reviews the literature on daptomycin in ICU patients with sepsis, focusing on dosing and PK and PD parameters.

Identification of Synthetic and Natural Host Defense Peptides with Leishmanicidal Activity

Leishmaniaparasites are a major public health problem worldwide. Effective treatment of leishmaniasis is hampered by the high incidence of adverse effects to traditional drug therapy and the emergence of resistance to current therapeutics. A vaccine is currently not available. Host defense peptides have been investigated as novel therapeutic agents against a wide range of pathogens. Here we demonstrate that the antimicrobial peptide LL-37 and the three synthetic peptides E6, L-1018, and RI-1018 exhibit leishmanicidal activity against promastigotes and intramacrophage amastigotes ofLeishmania donovaniandLeishmania major We also report that theLeishmaniaprotease/virulence factor GP63 confers protection toLeishmaniafrom the cytolytic properties of alll-form peptides (E6, L-1018, and LL-37) but not thed-form peptide RI-1018. The results suggest that RI-1018, E6, and LL-37 are promising peptides to develop further into components for antileishmanial therapy.

High-dose daptomycin therapy for staphylococcal endocarditis and when to apply it

Infective endocarditis (IE) continues to present a large burden to the health-care system. Staphylococcus aureus, the leading pathogen associated with the disease, has always proven difficult to treat. Increasing numbers of S. aureus isolates are demonstrating reduced susceptibility to vancomycin, and therapeutic options are limited. Daptomycin is frequently employed when vancomycin therapy proves unsuccessful or when vancomycin minimum inhibitory concentration (MIC) values rise above 1 mg/L. Currently, daptomycin is FDA-approved at a dose of 6 mg/kg/day for the treatment of S. aureus bacteremia and associated right-sided endocarditis. However, numerous in vitro and clinical studies suggest that daptomycin doses up to 12 mg/kg/day may provide improved efficacy and resistance prevention. Additionally, high-dose daptomycin has demonstrated excellent safety. Together, these data suggest a role for high-dose daptomycin in staphylococcal IE patients who are severely ill, previously failed therapy with vancomycin, or possess a S. aureus isolate with an elevated vancomycin MIC.

Activity of daptomycin or linezolid in combination with rifampin or gentamicin against biofilm-forming Enterococcus faecalis or E. faecium in an in vitro pharmacodynamic model using simulated endocardial vegetations and an in vivo survival assay using Galleria mellonella larvae

Enterococci are the third most frequent cause of infective endocarditis. A high-inoculum stationary-phase in vitro pharmacodynamic model with simulated endocardial vegetations was used to simulate the human pharmacokinetics of daptomycin at 6 or 10 mg/kg of body weight/day or linezolid at 600 mg every 12 h (q12h), alone or in combination with gentamicin at 1.3 mg/kg q12h or rifampin at 300 mg q8h or 900 mg q24h. Biofilm-forming, vancomycin-susceptible Enterococcus faecalis and vancomycin-resistant Enterococcus faecium (vancomycin-resistant enterococcus [VRE]) strains were tested. At 24, 48, and 72 h, all daptomycin-containing regimens demonstrated significantly more activity (decline in CFU/g) than any linezolid-containing regimen against biofilm-forming E. faecalis. The addition of gentamicin to daptomycin (at 6 or 10 mg/kg) in the first 24 h significantly improved bactericidal activity. In contrast, the addition of rifampin delayed the bactericidal activity of daptomycin against E. faecalis, and the addition of rifampin antagonized the activities of all regimens against VRE at 24 h. Also, against VRE, the addition of gentamicin to linezolid at 72 h improved activity and was bactericidal. Rifampin significantly antagonized the activity of linezolid against VRE at 72 h. In in vivo Galleria mellonella survival assays, linezolid and daptomycin improved survival. Daptomycin at 10 mg/kg improved survival significantly over that with linezolid against E. faecalis. The addition of gentamicin improved the efficacy of daptomycin against E. faecalis and those of linezolid and daptomycin against VRE. We conclude that in enterococcal infection models, daptomycin has more activity than linezolid alone. Against biofilm-forming E. faecalis, the addition of gentamicin in the first 24 h causes the most rapid decline in CFU/g. Of interest, the addition of rifampin decreased the activity of daptomycin against both E. faecalis and VRE.

Daptomycin activity tested against 164457 bacterial isolates from hospitalised patients: summary of 8 years of a Worldwide Surveillance Programme (2005-2012)

We report the results of 8 years (2005-2012) of the Daptomycin Surveillance Programme Worldwide. Consecutive non-duplicate bacterial isolates (prevalence design) were collected from patients with documented infections in 410 medical centres and were susceptibility tested by reference broth microdilution methods. A total of 164457 Gram-positive isolates were evaluated, including 97542 Staphylococcus aureus, 21413 coagulase-negative staphylococci (CoNS), 29619 enterococci and 15883 β-haemolytic streptococci. The prevalence of daptomycin-non-susceptible isolates was extremely low for all species in all geographic regions. Overall, the highest occurrence of non-susceptible isolates was observed among CoNS (0.19%), followed by Enterococcus faecium (0.18%), S. aureus (0.05%), Enterococcus faecalis (0.02%) and β-haemolytic streptococci (0.00%). Moreover, no trend towards increased daptomycin resistance (non-susceptibility) was observed for any species in any geographic region during the study interval. Against S. aureus, the daptomycin MIC(50/90) was 0.25/0.5 mg/L in all geographic regions (99.95% susceptible overall). Only 53 daptomycin-non-susceptible S. aureus isolates were observed and the vast majority (49; 92.5%) had a daptomycin MIC value only 1 log(2) dilution above the published susceptible breakpoint. Daptomycin was also active against CoNS (MIC(50/90), 0.25/0.5 mg/L; 99.81% susceptible), E. faecalis (MIC(50/90), 1/2 mg/L; 99.98% susceptible), E. faecium (MIC(50/90), 2/4 mg/L; 99.82% susceptible) including vancomycin-non-susceptible isolates (4521 isolates; MIC(50/90), 2/2 mg/L; 99.76% susceptible), and β-haemolytic streptococci (MIC(50/90), ≤0.06/0.25 mg/L; 100.0% susceptible). In conclusion, daptomycin has remained very active against indicated species worldwide, and no significant year-to-year or regional variation in daptomycin activity has been detected.

Daptomycin activity against uncommonly isolated streptococcal and other gram-positive species groups

A total of 1,356 clinical isolates were tested against daptomycin by broth microdilution methods. Daptomycin was active against seven groups of viridans group streptococci (MIC50 and MIC90 values ranging from ≤0.06 and ≤0.06 μg/ml [Streptococcus bovis and Streptococcus dysgalactiae] to 0.5 and 1 μg/ml [Streptococcus mitis, Streptococcus oralis, and Streptococcus parasanguinis], respectively), beta-hemolytic streptococci serogroups C, F, and G (MIC50 and MIC90, ≤0.06 to 0.25 and 0.12 to 0.25 μg/ml, respectively), Corynebacterium spp. (MIC50 and MIC90, ≤0.06 and 0.12 μg/ml, respectively), and Micrococcus spp. (MIC50 and MIC90, ≤0.06 and 0.25 μg/ml, respectively). Listeria monocytogenes exhibited higher daptomycin MICs (MIC50 and MIC90, 2 and 4 μg/ml, respectively) than other tested organisms.

Modes of action of Leishmanicidal antimicrobial peptides

Leishmaniasis is one of the major neglected tropical diseases of the world. It is present in 88 countries with an estimated number of 500,000 cases of visceral leishmaniasis and 1.5 million cases of cutaneous disease. No effective vaccinations are available against leishmaniasis and the efficacy of existing treatments is compromised due to the emergence of drug resistance. Thus, there is an urgent need to develop new compounds with antileishmanial activity. Antimicrobial peptides have potential as novel antileishmanial therapy, either for use alone or in combination with current drug regimens. The modes of action of these peptides against Leishmania includes: membrane disruption leading to necrotic cell death; induction of apoptosis; binding to intracellular target(s); and indirect effects via immunomodulation of host immune cells. This article reviews the mechanisms of action of antimicrobial peptides with leishmanicidal activity.

Treatment of Gram-positive left-sided infective endocarditis with daptomycin

The aim of this study was to evaluate the effectiveness of daptomycin in left-sided infective endocarditis (IE) patients. Fourteen patients with left heart endocarditis, monitored with a diagnosis of IE based on modified Duke criteria between July 2010 and May 2011, and receiving daptomycin as monotherapy, were enrolled. The success of daptomycin in these patients was revealed with improvements in microbiological, biochemical, and radiologic findings, as well as physical examination findings. Patient average age was 63.5 ± 14.2 years (36-80 years); 8 (57 %) were men and 6 (43 %) women. The pathogens methicillin-resistant Staphylococcus aureus (71.5 %), Streptococcus mutans (21.5 %), and methicillin-sensitive Staphylococcus aureus (7 %) were isolated from our patients. Daptomycin was used in initial treatment in 5 (36 %) patients; treatment was subsequently modified to daptomycin in 9 (64 %) patients as a consequence of drug serum level insufficiency, agent sensitivity to the drug administered, or drug side effects. Thirteen patients were discharged in a healthy condition, with successful surgical treatment in 5 (36 %). Only 1, an 80-year-old IE patient, was lost from advanced cardiac failure. No significant side effects were seen in any patient receiving daptomycin. The most frequent side effects were minimal rises in serum CPK levels during treatment; these values returned to normal after treatment. Daptomycin can be used successfully in left heart endocarditis with no significant side effects. Studies involving a wider patient series are now needed to support the use of daptomycin in left heart endocarditis.

Indications for daptomycin use in endocarditis and pacemaker lead infection and outcomes in Leeds, UK

Infective endocarditis now comprises an increasingly complex mixture of endocardial infections, with staphylococci as the predominant cause. Although vancomycin has been an important therapeutic option for several decades, reduced susceptibility is emerging. Daptomycin is a relatively new antimicrobial agent, approved for right-sided endocarditis, but the data for other forms of endocarditis are limited. Here we report clinical data from the Leeds Endocarditis Service (Leeds, UK) for 19 patients treated with daptomycin between January 2007 and December 2009. The majority of cases were caused by staphylococci. All patients were treated with 6 mg/kg with a median treatment duration of 29 days. In total, 53% of patients were cured with antimicrobial regimens, which included daptomycin. Four patients (21%) died during therapy or within 30 days of stopping treatment. The current series is representative of everyday clinical practice and reflects the current difficulties in managing endocarditis.

Endocarditis caused by methicillin-susceptible Staphylococcus aureus with reduced susceptibility to vancomycin: a case report

Introduction

Staphylococcus aureus is the most common cause of acute infective endocarditis.

Recent reports have described heteroresistance to vancomycin associated with methicillin-resistant Staphylococcus aureus. We present the first case report in Argentina of the failure of treatment with vancomycin in endocarditis caused by methicillin-susceptible Staphylococcus aureus containing subpopulations with reduced susceptibility to vancomycin.

Case presentation

We report the case of a 66-year-old Hispanic man with infective endocarditis complicated by septic emboli in the lumbosacral spine and the left iliopsoas muscle. This disease was caused by methicillin-susceptible Staphylococcus aureus containing subpopulations with reduced susceptibility to vancomycin. He was initially treated with cephalothin and gentamicin but developed a rash caused by beta-lactams and interstitial nephritis. For that reason, the treatment was subsequently switched to vancomycin but he failed to respond. The infection resolved after administration of vancomycin in combination with gentamicin and rifampin.

Conclusion

Our case report provides important evidence for the existence of subpopulations of methicillin-susceptible Staphylococcus aureus that have reduced susceptibility to vancomycin which would account for treatment failure. Our case raises an alert about the existence of these strains and highlights the need to determine the vancomycin minimum inhibitory concentration of Staphylococcus aureus to screen for the presence of strains that have reduced vancomycin susceptibility at different infection sites.

Use of daptomycin in complicated cases of infective endocarditis

Infective endocarditis (IE) is a serious form of infection with a high mortality. Medical management can be a challenge because of organ dysfunction, lack of clinical response or allergy to the recommended antibiotics. Daptomycin is a lipopeptide antibiotic with a potent bactericidal activity against Gram-positive bacteria. There are limited data on the use of daptomycin in complicated cases of IE. We aim to report our experience of daptomycin use in complicated cases of IE through a prospective observational study (from 1 October 2008 to 30 September 2009). Daptomycin was prescribed for cases that were either unresponsive or allergic to the standard therapy. Clinical characteristics and outcomes were reviewed. Success was defined as clinical improvement accompanied with the resolution of laboratory markers of sepsis and continuation of the above findings for at least 8 weeks after the end of therapy. Eight cases were evaluable. Native and prosthetic valves were involved in equal proportions. The range of organisms was wide: Staphylococcus aureus, two cases; S. epidermidis, two cases; streptococci, two cases; and Enterococcus faecalis, two cases. The median duration of therapy was 42 days. All patients were successfully treated. Daptomycin was well tolerated. Daptomycin is useful in the management of complicated cases of IE.

Observational study of the epidemiology and outcomes of vancomycin-resistant Enterococcus bacteraemia treated with newer antimicrobial agents

Vancomycin-resistant Enterococcus bloodstream infections (VRE-BSI) are a growing problem with few clinical trials to guide therapy. We conducted a retrospective study of management and predictors of mortality for VRE-BSI at a tertiary-care centre from January 2005 to August 2008. Univariate and multivariable analyses examined the relationship of patient characteristics and antibiotic therapy with 30-day all-cause mortality. Rates of VRE-BSI increased from 0·06 to 0·17 infections/1000 patient-days (P=0·03). For 235 patients, 30-day mortality was 34·9%. Patients were primarily treated with linezolid (44·2%) or daptomycin (36·5%). Factors associated with mortality were haemodialysis [odds ratio (OR) 3·2, 95% confidence interval (CI) 1·6-6·3, P=0·007], mechanical ventilation (OR 3·7, 95% CI 1·3-10·4, P=0·01), and malnutrition (OR 2·0, 95% CI 1·0-4·0, P=0·046). Use of linezolid, but not daptomycin (P=0·052) showed a trend towards an association with survival. In conclusion, VRE-BSI is a growing problem, associated with significant 30-day mortality. Multiple factors were associated with poor outcomes at our hospital.

Pre-clinical experience with daptomycin

Daptomycin is a broad-spectrum, bactericidal agent active against Gram-positive bacteria, acting largely and unusually through membrane depolarization. Activity is markedly affected in vitro by the availability of calcium ions, and its high molecular weight with associated poor diffusion means that conventional disc diffusion testing is not reliable (and as a consequence not available). In order to allow susceptibility categorization, it is recommended that the MIC be determined in the presence of a defined calcium concentration. The activity of daptomycin is concentration-dependent with a prolonged post-antibiotic effect. It has linear pharmacokinetics, with a half-life of 8-9 h, the primary route of excretion is renal, it exhibits serum protein binding of approximately 92% and there is no interaction with the P450 cytochrome. Daptomycin is inactivated by surfactant in the lung and, in consequence, is not recommended for the treatment of respiratory infections. Daptomycin is currently licensed for the treatment of complicated skin and soft tissue infections and for bacteraemia and right-sided endocarditis due to methicillin-susceptible and -resistant Staphylococcus aureus. To date, daptomycin-resistant bacteria have rarely been isolated from patients, although increases in vancomycin MIC may be linked to reduced susceptibility to daptomycin. Close monitoring of resistance is essential to maintain the clinical utility of the drug. Using once-daily dosing, daptomycin has been generally well tolerated; however, weekly monitoring of creatinine phosphokinase is recommended, as myopathy in skeletal muscles has been seen, albeit rarely. The rapid bactericidal action of daptomycin makes it a useful addition to the therapeutic armamentarium for the treatment of Gram-positive infections, providing a valuable alternative to vancomycin when it is inappropriate or resistance is a problem.

Daptomycin in endocarditis and bacteraemia: a British perspective

Assessment of the place of daptomycin in the treatment of endocarditis and bacteraemia requires assimilation of data from one open-label randomized comparative clinical trial sized for equivalence, from registry data and from case reports. Selected relevant animal models and in vitro data are also considered in an effort to produce an integrated assessment of the current place of daptomycin in treatment. The evidence for the use of daptomycin is best in Staphylococcus aureus bacteraemia and endocarditis, but also includes some data on infections due to Enterococcus spp., especially if vancomycin-resistant. The emergence of resistance in a minority of patients on current dose regimens may mean that trials have to be repeated with higher doses, or the drug used in a combined therapy where rifampicin may be the best choice. In general, equivalence to comparator antibiotic regimens and a correlation for in vitro and in vivo findings have been demonstrated, but there are important gaps in the clinical data including a comparative equivalence trial in streptococcal and enterococcal endocarditis. Clinical benefit might be anticipated, but has not been proved, over aminoglycoside-containing regimens, and economic assessments are critical in the decision as to when and how daptomycin is deployed.